In his personal blog, Open Attribution founder James O’Claire conducted s survey of popular trackers utilized by Android Apps. He found that almost 50% of these apps rely on 4 trackers:
There are 5 large mobile app trackers, also called MMPs. Those are AppsFlyer, Adjust (owned by AppLovin), Branch and Yandex AppMetrica. These mobile attribution companies track users data across many apps. For Android nearly 50% of all apps contain a mobile app tracker and for iOS a bit less at 1 in 4 apps. This number of course skews much higher for apps and games that spend money on advertising to gain users and thus rely on mobile app attribution.
A quick note on the methodology: These numbers are based on AppGoblin’s data for de-compiled Android and iOS apps which is currently around 40k. This is only a fraction of the ~2m active Android and iOS Apps on the App Stores but is ranked by the most popular apps.